We present and analyze a nonlinear dynamical system modelling forest-pests interactions and the way they are affected by acidic deposition. The model includes mechanisms of carbon and nitrogen exchange between soil and vegetation, biomass decomposition and microbial mineralization, and defoliation by pest grazers, which are partially controlled by avian or mammalian predators. Acidic deposition...

This paper investigates kinetic behavior of a planetary rover with attention to tire-soil traction mechanics and articulated body dynamics, and thereby study the control when the rover travels over natural rough terrain. Experiments are carried out with a rover test bed to observe the physical phenomena of soils and to model the traction mechanics, using the tire slip ratio as a state variable....

In this paper, an elastoplastic constitutive model is presented for predicting sandy soil behavior under monotonic and cyclic loadings. The model is based on the CJS3 model that takes into account deviatoric and isotropic mechanisms of plasticity. The flow rule in deviatoric mechanism is non-associated and a kinematic hardening law controls the evolution of the yield surface. In the present s...

Vertisols are clay soils that are common in the monsoonal and dry warm regions of the world. One of the characteristics of these soil types is to form deep cracks during periods of extended dry, resulting in significant variation of the soil and hydrologic properties. Understanding the influence of these varying soil properties on the hydrological behavior of the system is of considerable inter...

abstract in order to study the chemical behavior of nickel and cadmium in the presence of organic matter, an experiment with two different soils (4 and 30 percent caco3), two different texture (8 and 40 percent clay), two levels of nickel (0 and 100 mg.kg-1), two levels of cadmium (0 and 25 mg.kg-1) and organic matter in the form of sewage sludge in two levels (0 and 100 t. ha-1), at three time...

understanding people’s ecological behaviors and the impacts of human activities on natural environment is one of the most important concepts in ecological psychology research. the purpose of this study was to investigate causal relationship between factors and maize growers’ ecological behavior concerning the application of external inputs such as water, fertilizers, chemical pesticides, and ma...

The Direct Simple Shear (DSS) test is one of the laboratory element testing devices that has been widely used to assess soil behavior. Although the DSS test is considered to simulate the cyclic shear loading mode from the earthquakes in an effective manner, the most commonly used versions of the test device (such as the NGI-type DSS device) do not provide means of measuring the lateral stresses...